wiring in electric fuel pump - The 1947 - Present Chevrolet & GMC Truck Message Board Network

72blue · 02-22-2009, 11:05 PM

Hello all. I am new. I have a 72 K10 that i have been restoring and have reached the wiring. A holley red fuel pump is installed and I have a M&H harness for the rest of the pickup. I have read about other members that have had problems with their engines not shutting off after they have installed a relay with their electric fuel pump; as this might be just a installation error, I would like some direct input. What kind of relay do I need; single post or double? What is the difference in this case? Where should I locate it? I would appreciate any knowledge. Thanks, James

Longhorn Man · 02-22-2009, 11:49 PM

welcome to the board.
A relay, while a great idea to feed your pump full system voltage, will do nothing to prevent the condition you described.
That is usually caused by a cooling fan producing voltage and feeding the coil just enough power to run the engine.

*MonteSS454* · 02-23-2009, 12:36 AM

Just splicing the power wire to an ign on/constant on would be just fine. Thats how mine is hooked up and I haven't had a problem yet.

Andy4639 · 02-23-2009, 02:05 AM

Any late model fuel injection pump is ran with a relay. The relay's I have used for stuff have worked great with not any problems.

72blue · 02-23-2009, 03:10 AM

Painless has two different relays. A single post and a double. Which is the one I need for this use? My fuel pump is located on the passenger frame rail just under the rear of the cab. Where would the relay go in a perfect would? In the cab or closer to the battery?
Thanks, James

jgreene0717 · 02-23-2009, 03:15 PM

Just depends on your preference you could locate by battery on fender or core support. Inside you could mount underdash. I would use a bosch 30 amp relay here is a pic. Hook pin 30 to battery positive using fusible link. Pin 86 to ground. Pin 85 to ignition source at fuse panel also us fusible link. Pin 87 to fuel pump positive and that is it. You can purchase a 30 amp bosch style relay at any parts store.

72blue · 02-23-2009, 11:54 PM

Great. Thanks everyone for the help. This helps me a bunch.
James.

Andy4639 · 02-24-2009, 12:09 AM

You can pick these up as said at parts stores or go to the local yard and get all you want out of any late model car. You may even get the holders for them also.

72blue · 02-26-2009, 02:15 AM

Got some at a parts store for less than $20. Now comes the fun part.

02-22-2009, 11:05 PM	#1
72blue Registered User Join Date: Feb 2009 Location: arroyo grande, ca Posts: 206	wiring in electric fuel pump Hello all. I am new. I have a 72 K10 that i have been restoring and have reached the wiring. A holley red fuel pump is installed and I have a M&H harness for the rest of the pickup. I have read about other members that have had problems with their engines not shutting off after they have installed a relay with their electric fuel pump; as this might be just a installation error, I would like some direct input. What kind of relay do I need; single post or double? What is the difference in this case? Where should I locate it? I would appreciate any knowledge. Thanks, James

02-22-2009, 11:49 PM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: wiring in electruc fuel pump welcome to the board. A relay, while a great idea to feed your pump full system voltage, will do nothing to prevent the condition you described. That is usually caused by a cooling fan producing voltage and feeding the coil just enough power to run the engine.

02-23-2009, 12:36 AM	#3
MonteSS454 Account Suspended Join Date: Jun 2007 Location: Claremore, Oklahoma Posts: 821	Re: wiring in electruc fuel pump Just splicing the power wire to an ign on/constant on would be just fine. Thats how mine is hooked up and I haven't had a problem yet.

02-23-2009, 02:05 AM	#4
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Re: wiring in electruc fuel pump Any late model fuel injection pump is ran with a relay. The relay's I have used for stuff have worked great with not any problems. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

02-23-2009, 03:10 AM	#5
72blue Registered User Join Date: Feb 2009 Location: arroyo grande, ca Posts: 206	Re: wiring in electruc fuel pump Painless has two different relays. A single post and a double. Which is the one I need for this use? My fuel pump is located on the passenger frame rail just under the rear of the cab. Where would the relay go in a perfect would? In the cab or closer to the battery? Thanks, James

02-23-2009, 03:15 PM	#6
jgreene0717 Jason Join Date: Sep 2008 Location: Wetumpka, AL Posts: 152	Re: wiring in electruc fuel pump Just depends on your preference you could locate by battery on fender or core support. Inside you could mount underdash. I would use a bosch 30 amp relay here is a pic. Hook pin 30 to battery positive using fusible link. Pin 86 to ground. Pin 85 to ignition source at fuse panel also us fusible link. Pin 87 to fuel pump positive and that is it. You can purchase a 30 amp bosch style relay at any parts store. Attached Images

02-23-2009, 11:54 PM	#7
72blue Registered User Join Date: Feb 2009 Location: arroyo grande, ca Posts: 206	Re: wiring in electruc fuel pump Great. Thanks everyone for the help. This helps me a bunch. James.

02-24-2009, 12:09 AM	#8
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Re: wiring in electruc fuel pump You can pick these up as said at parts stores or go to the local yard and get all you want out of any late model car. You may even get the holders for them also. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

02-26-2009, 02:15 AM	#9
72blue Registered User Join Date: Feb 2009 Location: arroyo grande, ca Posts: 206	Re: wiring in electruc fuel pump Got some at a parts store for less than $20. Now comes the fun part.

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